This invention relates to road/rail level-crossings, and in particular to the installation of the rubber interface strips that fit between the metal rail and the asphalt or concrete of the road.
Rubber strips of the kind with which the invention is concerned are shown, for example, in patent publication CA-1,194,010 (EPTON, Sep. 24, 1985).
A problem with the rubber strip interface systems has been in the manner of attaching the rubber strip to the rail. It is necessary for the strips to be held firmly against the sides of the rail while the asphalt or concrete is being applied. If the strips can become loose relative to the rails at this time, the effect is that the road material cannot be properly compacted, which can have a serious effect on the service life of the crossing. When a crossing needs repair, it is usually because the road material has cracked or crumbled particularly at the line where the road material touches the rubber strips, and care in keeping the strips tight against the rails when the road material is being applied can make a difference of several years before the onset of crumbling at this line. The major purpose in providing rubber interface strips is to protect the road material from crumbling, but the system can only achieve its potential in this regard if the strips are held firmly against the rails when the road surface is being applied.
Once the road surface has been applied, and has hardened, the road material itself acts to hold the strips against the rails. That is to say, the road material supports the strips, while at the same time, of course, the strips support the road material.
The present invention is aimed at making it possible to squeeze the rubber pieces tightly against the side of the rail with a strong and reliable gripping force. It is also an aim that the means for applying the force can be assembled, and the heavy squeezing forces can be generated, using inexpensive components, which can be installed simply and safely.
While repairs are being carried out to a road-rail crossing, it is usually necessary to close the crossing to (road) traffic. Therefore, it is important that the work be completed quickly. Since the work is done relatively infrequently at a given location, it is not uncommon for the work crew to include many workers who have never worked on a crossing before. While the work should be done quickly, the emphasis is not that minutes count, but rather that the work must be completed within the allowed window of time. The designer of the repair system should see to it that the work can be completed without the need for special tools, and in a manner that requires no more than a minute or two of training. Safety of workers who are generally unfamiliar with the tasks is important. It is important that the preparations prior to pouring the asphalt or concrete be easy to inspect; i.e the engineer should be able to tell at a glance that all the work has been completed and has been done properly. The less time and skill he has to expend in checking, and the more plainly obvious it is that incomplete work is incomplete, the better. It is very expensive to come back later to correct any problems.
Traditionally, in order to hold a rubber interface strip against the side of the rail, a spike has been driven partially into the wood of the cross-tie, and the protruding head of the spike bent over until it touches the rubber. The spike-head is bent over by striking it in a lateral direction with a hammer. Such a system, i.e bending partially-driven spikes over into contact with the strips, contains the potential for a number of problems, such as damage to the wood, improper bending over of the spike head, etc.
An example of the bent-over spike system is shown in the publication entitled EPTON RAILSEAL.
In many jurisdictions, bending the spikes over is unacceptable, not least because of the high risk of injury to the installation workers. Also, of course, when the cross-ties are made of concrete, spikes cannot be driven-in in any event. For such cases, U-shaped spring-clips have been proposed, which lie underneath the rail, the arms of the spring-clip being bent apart in order to load the rubber strips laterally against the sides of the rail. The problem with the traditional spring-clip is that it is difficult to apply the heavy forces necessary to install the spring-clip into place over the strips, at least in the absence of elaborate special tools. It is recognized that the skill level required for installing these spring-clips efficiently (and safely) is somewhat outside the traditional level at which contractors for repairs to level-crossings operate. In fact, the skill level needed to install spring-clips is unlike that needed generally for the rest of the tasks involved when repairing level-crossings, and the contractor does not wish to engage specially-trained operators just for that one task.
Indeed, it may be pointed out that the task of securing the rubber strips by side-hammering partially-driven spikes is not in keeping either with the rest of the tasks involved when repairing level-crossings, which is another reason why bending spikes over is not favoured. Even so, driving railway spikes is a widespread recognized skilled trade, whereas installing spring-clips is not.
An example of the traditional type of U-shaped spring-clip is shown in the publication entitled EPTON RAILSEAL FOR CONCRETE TIE APPLICATION.
It is another aim of the present invention that the system for securing the rubber strips to the sides of the rails be foolproof, whereby even an unskilled novice labourer cannot assemble the components wrongly, nor can he hurt himself.
The system of the invention involves the use of a metal (e.g. spring-steel) spring-clip. The spring-clip is of a U-configuration, having a central beam and having left and right arms integrated therewith. Left and right tappets are arranged for contact with left and right tappet-receiving points (e.g. grooves) on the side-surfaces of the strips. In the invention, the tappets are adjustable as to their relative separation. The tappets can be forcefully moved or adjusted apart, preferably, for example, by means of a screw thread connection between the tappet and the arm. The following procedure may be used when installing the strips: first, the clips are manipulated underneath the rail; then, the strips are placed against the rail; then, the clips are manoeuvred into place around the strips; then, the tappet distance is adjusted to take up the slack and to bring the tappets into contact with the strips; then force is applied between the tappets, which compresses the strips against the sides of the rail, and bends the two arms apart, thereby clamping the strips resiliently to the sides of the rail.